This invention relates to an internal combustion engine equipped with a turbocharger driven by exhaust gas pressure, and more particularly to a maximum vehicle speed limiting device of the engine equipped with the turbocharger.
It is well known in the art, that internal combustion engines are equipped with turbochargers. The turbocharger has a turbine wheel which is fixedly connected through a common shaft to a compressor wheel. The compressor wheel is driven by the rotated turbine wheel to pressurize intake air inducted into the combustion chambers of the engine. In such an engine, the charging efficiency is considerably high improving engine power output to a considerable extent. As a result, the maximum speed of a motor vehicle such as an automobile on which the above mentioned engine is mounted can be greatly increased.
However, motor vehicles having an excessively high maximum speed are undesirable from a point of view of safe driving. Accordingly, it is necessary to limit the maximum speed of the vehicle to a safe level. In this regard, the following measures have been already proposed:
(1) the maximum power output of the engine is suppressed;
(2) engine speed is suppressed by de-energizing the ignition system of the engine. However, the former measure is undesirable since acceleration performance is also unavoidably deterioratated. The latter measure is also undesirable since engine power output is abruptly lowered when the ignition system is de-energized accompanying abrupt decrease in vehicle speed which is very dangerous for vehicle occupants.